[FFmpeg-cvslog] avcodec/evc_parse: Check tid

[Michael Niedermayer]

ffmpeg | branch: release/6.1 | Michael Niedermayer <michael at niedermayer.cc> | Thu Oct  5 00:19:53 2023 +0200| [3d1ca4c3ff28905258f1382a91fd17d3cbea7800] | committer: Michael Niedermayer

avcodec/evc_parse: Check tid

The check is based on not infinite looping. It is likely
a more strict check can be done

Fixes: Infinite loop
Fixes: 62473/clusterfuzz-testcase-minimized-ffmpeg_BSF_EVC_FRAME_MERGE_fuzzer-5719883750703104
Fixes: 62765/clusterfuzz-testcase-minimized-ffmpeg_dem_EVC_fuzzer-6448531252314112
Fixes: 63378/clusterfuzz-testcase-minimized-ffmpeg_dem_MPEGPS_fuzzer-6504993844494336

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: "Dawid Kozinski/Multimedia (PLT) /SRPOL/Staff Engineer/Samsung Electronics" <d.kozinski at samsung.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 68cc1744db828e929b74f96478c18f1d226510be)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3d1ca4c3ff28905258f1382a91fd17d3cbea7800
---

 libavcodec/evc_parse.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/evc_parse.c b/libavcodec/evc_parse.c
index 255706ce61..43b8dabf8b 100644
--- a/libavcodec/evc_parse.c
+++ b/libavcodec/evc_parse.c
@@ -174,6 +174,9 @@ int ff_evc_derive_poc(const EVCParamSets *ps, const EVCParserSliceHeader *sh,
         } else {
             int SubGopLength = 1 << sps->log2_sub_gop_length;
 
+            if (tid > (SubGopLength > 1 ? 1 + av_log2(SubGopLength - 1) : 0))
+                return AVERROR_INVALIDDATA;
+
             if (tid == 0) {
                 poc->PicOrderCntVal = poc->prevPicOrderCntVal + SubGopLength;
                 poc->DocOffset = 0;